[关键词]
[摘要]
高能级强夯的加固效果显著,应用范围越来越广泛,有效加固深度是评判加固效果和确定强夯方案的重要指标。以10000 kN·m高能级强夯加固某抛填路基工程为背景,采用FLAC 3D有限差分软件进行单点多次夯击的强夯数值模拟,以夯击后的应力为标准来计算有效加固深度。结果表明:随夯击次数的增加,有效加固深度先增大后稳定,6击后有效加固深度的增幅极小。经正交试验和极差分析得到土体参数对强夯有效加固深度的敏感性排序。落距和锤重与有效加固深度呈正相关关系,锤径则为负相关关系。锤重对有效加固深度的影响大于落距,在夯击能相同时,重锤低落所得到的累计夯沉量与有效加固深度均更大。提出强夯有效加固深度估算公式,并实现了量纲统一,该公式与模拟结果偏差较小,可供同类型强夯工程参考。
[Key word]
[Abstract]
The high energy dynamic compaction has been effective in a wide range of applications, effective reinforcement depth is an important indicator for evaluating the reinforcement effect and determining the dynamic consolidation plan. In this paper, taking a project of 10000kN·m high energy dynamic compaction for filled subgrade as a background, the finite difference software FLAC 3D was used to perform multiple dynamic compaction analysis. The stress after tamping was considered as a criterion to calculate the effective reinforcement depth. The results show that with the increase in the number of drops, the effective reinforcement depth first increases and then stabilizes. The growth rate of effective reinforcement depth after six drops is extremely small. The sensitivity ranking of soil parameters on the effective reinforcement depth is obtained by orthogonal test and extreme difference analysis. The drop distance and hammer weight are positively correlated with the effective reinforcement depth, while the hammer diameter is negatively correlated. The impact of hammer weight on the effective reinforcement depth is greater than the drop distance. The combination of heavy hammer and low drop distance has greater cumulative settlement and effective reinforcement depth under the same tamping energy. The formula for estimating the effective reinforcement depth of high energy dynamic compaction is proposed, and the uniformity of dimensions is achieved, which has a small deviation from the simulation results. It can provide reference for the same type of dynamic compaction project.
[中图分类号]
TU472.1;U416
[基金项目]
浙江省交通运输厅科技项目(2019035)